Some naturally-occurring compounds exhibit various characteristics attributed to their asymmetric structure. Of physiologically active substances having an asymmetric structure, many of those useful for humans are confined to the respective specific antipode. This tendency is particularly conspicuous in the field of pharmaceuticals, agricultural chemicals, pheromones, and food additives. It is known in these fields that a racemic mixture may have a markedly reduced effect or rather exhibit a counter effect. The field of perfumes is no exception to this tendency. For example, l-menthol has the odor of mint; d-carvone has the odor of Caraway L.; and d-nootkatone has the odor of grapefruit. Each of these optical antipodes is different from or stronger than the respective other optical antipodes in odor. The latest examples of such a phenomenon are observed in .alpha.-ionone, hydroxycitronellal, and rose oxide. For the detail, reference can be made to Kaqaku Sosetsu, No. 14, Ch. 6 "Aji to Nioi no Kagaku"(1976).
Therefore, development of optically active perfume components as well as development of novel perfumes would lead to development of optical antipodes having a new odor or usefulness and are of industrial significance.
With respect to 3-(2,2,6-trimethylcyclohexan-1-yl)-propanol derivatives, compounds known to have a wood-like fragrance or an amber-like fragrance include 1-(2,2,6-trimethylcyclohexan-1-yl)pentan-3-ol having an ethyl group as the alkyl moiety (see West German Patent Application (OLS) No. 2,455,761), 1-(2,2,6-trimethylcyclohexan-1-yl)hexan-3-ol having a propyl group as the alkyl moiety (see JP-A-62-70314, JP-B-1-38438, JP-B-59-18373, JP-A-61-191636, and JP-B-62-16935; the terms "JP-A" and "JP-B" as used herein mean an "unexamined published Japanese patent application" and an "examined Japanese patent publication", respectively), and 5-methyl-1-(2,2,6-trimethylcyclohexan-1-yl)hexan-3-ol having an isobutyl group as the alkyl moiety (see USSR Patent 1,082,780).
JP-B-1-38438 discloses a composition of 1-(2,2,6-trimethylcyclohexan-1-yl)hexan-3-ol comprising 80% or more of a trans isomer and not more than 20% of a cis isomer.
Since these cis and trans isomers each has an asymmetric carbon atom in the molecule thereof, it is expected that there are a pair of enantiomers, i.e., (+)-isomer and (-)-isomer. However, the compounds disclosed in the above-cited references exist as a racemic mixture. No other study has been reported on synthesis or properties of the individual optical isomers.
The recent diversity of cosmetics and sanitary goods has created a new increasing demand for a perfume material which has high diffusibility, unique scent, high tastiness, high retention, satisfactory stability, and high safety. In particular, perfume materials having an amber-like fragrance and satisfying these requirements have been wanted.